Rail model - Executive Summary

Background

The full report is available from a link at the foot of this page.

FaberMaunsell was commissioned by the Department of Transport, Local Government and the Regions (DTLR) in May 2001 to develop a national rail model framework as part of the Department's multi-modal modelling package to test the Government's TEN Year Plan strategies.

The National Transport Model (NTM) played a key role in the formulation of the Government's Ten Year Plan for transport. Since then, it has been undergoing a comprehensive programme of development to make it more integrated and spatially oriented.

One important element in this development has been the creation and inclusion within the NTM framework of the National Rail Model (NRM), to enable the impact of various transport policies to be assessed in a truly multi-modal fashion. As such, the emphasis has been on developing a model capable of capturing the strategic interactions between rail and other modes, rather then aiming to model in detail demand on particular rail routes. Nonetheless, the NRM comprises a geographical representation of the entire rail network, covering all stations on the rail system and the London Underground, and demands for its use. This integrates with the core mode-choice model of the NTM, known as "Pass1".

The main driver of rail demand, in response to a policy change, is the Pass1 multi-modal demand model. Being multi-modal it can test the impacts of non-rail policies on rail demand and the impacts of rail policies on non-rail demand. This is a key strength of the NTM and the primary role of the detailed rail model is to support this by generating robust rail costs and distributing Pass1 generated rail demands to the required spatial detail.

Thus the impacts on transport users of, say, rail infrastructure investment could be modelled, including not just the initial modal shift from roads, but also any ensuing feedback effects via changes in the costs of rail travel. Similarly, the model can also be used to estimate the impact of road policy schemes on rail use.

On the technical side, the modelling is complicated by the different spatial structures of Pass1 and the NRM. Pass1 works through area types - with, for example, all medium-sized urban towns in the same area type - and distance bands. The NRM, on the other hand, uses "real" geography.

The study also included the development of a set of Rail Policy User interfaces which have provided a friendly and efficient environment for the user to specify, for model testing, various rail service and/or policy changes associated with the Ten Year Plan.

Study objectives

The brief provided a clear statement of the aim of the study as "To develop a rail modelling system, compatible with the Departmental Pass1 model, that can be operated by DTLR to produce estimates of the effect, on core outputs and outcomes, of different rail policy choices."

Key attributes of the model framework were to provide a user-friendly interface to enable the model to be run efficiently without the need for specific modeling expertise. The model framework has also to be flexible to accommodate future changes in the Pass1 structure and to enable the user to specify changes to key parameters.

The philosophy in the model development process was to avoid hard coding of any variables so that the user can test the sensitivity of the model outputs to key demand drivers and to incorporate new data as it becomes available.